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Questions after two nights with APAP - Printable Version

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RE: Questions after two nights with APAP - vsheline - 07-14-2019

(07-12-2019, 10:37 AM)finitethis Wrote: Based on the feedback in this forum, I just completed night 3 with the following modifications:

* I reduced EPR from 3 to 1 to see if it helped with CA events.
* I reduced the min pressure from 6.6 to 6.2.

<snipped> 
I will say that the mask and pressure felt very natural from the start of lying down. I'm assuming this is because the reduced EPR was more comfortable for me?

See attached for full night OSCAR results and a two-min zoom in on a CA event. I'm not sure if I was awake when this CA event was recorded or not.


Hi finitethis,

In the two minute zoomed in portion of the Flow waveform showing a CA, the CA marked at 4:26.31 appears to me to be a “real” CA and I think you were asleep.

CAs are not uncommon, especially when starting PAP therapy. I think about a third of new users/patients have 5 or more of these per hour, and for at least half of the new users who initially have more than 5 per hour the CAs tend to gradually reduce to 1 or 2 per hour or less, as their system gets used to PAP therapy during the initial weeks or couple months of treatment. 

Notice that the resumption of the Flow is gradual when the CA ends. This is a classic characteristic of a CA. Obstructive events pretty much always end with sharp, large recovery breaths. 

Also notice that the CA was preceded by a few larger-than-normal breaths, after which the Flow waveform gradually decreased and stopped, which is how many CA events start. 

I think the pressure and EPR changes you made look good for now. Or, you could try reducing EPR to zero, but personally I have always preferred at least a little EPR (or at least a little “Pressure Support” which on a bilevel machine is similar to ResMed EPR). After several weeks you could try increasing EPR to see whether you prefer it that way and whether EPR no longer causes an excessive number of CA events. 

By the way, I suggest changing the vertical scale of your Flow waveform to perhaps +/- 80 (instead of +/- 155), to better see fine detail. 

When your Flow exceeds +/- 80 the peaks of the Flow waveform would be clipped, but I think it does not help much to know exactly how large the peaks are, but it is very helpful to see clearer detail during normal breathing. 

Take care,
Vaughn